High-pressure decorative laminates are laminated articles comprising plural layers of synthetic resin impregnated paper sheets consolidated or bonded together into a unitary structure under high heat and pressure. Conventionally, the decorative or print layer is a sheet of high quality cellulose fiber and fillers impregnated with a thermosetting condensation resin such as melamine-formaldehyde resin. The decorative sheet may be overlaid with a low basis weight transparent sheet, which is also a sheet of cellulose impregnated with melamine-formaldehyde resin. These sheets are bonded to a plurality of core or body sheets of a fibrous cellulosic material, usually unbleached kraft paper, impregnated with a thermosetting resin such as phenolformaldehyde resin. Typically, up to seven or eight or more core sheets are consolidated with a single decorative sheet and a single overlay sheet to form a decorative laminate.
Decorative laminates are widely employed in the building industry for use as counter tops, kitchen and bathroom work surfaces, wall panelings, floors, cabinets, partitions and doors. Because they are generally more durable than wood and provide an attractive appearance, decorative laminates are also popular in the furniture industry, primarily as tops for furniture such as tables and desks.
The extensive use of these decorative laminates is primarily due to their low cost, impact and abrasion resistance, durability, clarity, and their resistance to heat, ultraviolet light and mild chemicals.
Decorative laminates are conventionally made of a core or body comprising a plurality of sheets of a fibrous material such as kraft paper which can be impregnated with a thermosetting resin. A decorative sheet also known as a decor sheet is usually mounted on top of the core to hide or disguise the underlying core. The decor sheet typically comprises a fibrous sheet having either a design printed on it or it may be dyed or have pigments dispersed therethrough to provide a solid color decorative sheet.
In the preparation of solid color decorative sheets, the colorant or pigment is added to the pulp prior to forming the sheet on the paper making machine. This method has been limited to producing decorative sheets which have a uniformly solid color. If a decorative design, pattern or a kaleidoscope effect were desired on either a clear or colored decorative sheet, a separate printing process with a printing cylinder or plate specially made for each color and intensity was required. The resulting pattern is then present only as a thin surface layer which is easily abraded away.
Thus, it would be desirable to have a decorative sheet for use in decorative laminates which not only economically provides a decorative color but also a sheet in which multicolored patterns are created within the sheet, i.e., interspersed among the fibers to improve its appearance of localized single or multicolored patterns characteristics. The present invention provides such a decorative sheet, a method for preparing such decorative sheet, and a decorative laminate using such decorative sheet.